"For decades, the services had a defined-benefit system that vested after 20 years of service in an immediate annuity computed based on years of service and basic pay using a 2.5-percent multiplier. The 2016 National Defense Authorization Act created a new system called the Blended Retirement System (BRS) that changes the defined-benefit multiplier to 2.0 percent and adds two new components: a defined-contribution plan known as the Thrift Savings...